Version 4 SHEET 1 2260 1604 WIRE 128 880 128 848 WIRE 128 992 128 960 WIRE 128 1136 128 1072 WIRE 336 848 128 848 WIRE 336 1024 336 848 WIRE 336 1136 128 1136 WIRE 336 1136 336 1104 WIRE 384 1024 384 848 WIRE 384 1136 336 1136 WIRE 384 1136 384 1104 WIRE 464 848 384 848 WIRE 560 624 560 592 WIRE 560 720 560 688 WIRE 576 848 528 848 WIRE 576 1008 576 848 WIRE 576 1136 384 1136 WIRE 576 1136 576 1072 WIRE 688 592 560 592 WIRE 688 624 688 592 WIRE 688 768 688 704 WIRE 688 848 576 848 WIRE 688 848 688 768 WIRE 688 1008 688 848 WIRE 688 1136 576 1136 WIRE 688 1136 688 1088 WIRE 688 1184 688 1136 WIRE 736 768 688 768 WIRE 800 848 688 848 WIRE 864 768 800 768 WIRE 864 800 864 768 WIRE 864 960 864 896 WIRE 864 1008 864 960 WIRE 864 1136 688 1136 WIRE 864 1136 864 1088 WIRE 928 592 688 592 WIRE 1008 768 864 768 WIRE 1008 816 1008 768 WIRE 1008 1024 1008 896 WIRE 1008 1136 864 1136 WIRE 1008 1136 1008 1088 WIRE 1056 768 1008 768 WIRE 1120 960 864 960 WIRE 1184 592 1008 592 WIRE 1184 624 1184 592 WIRE 1184 768 1136 768 WIRE 1184 768 1184 704 WIRE 1184 912 1184 768 WIRE 1184 1136 1008 1136 WIRE 1184 1136 1184 1008 WIRE 1248 768 1184 768 WIRE 1344 768 1312 768 WIRE 1344 992 1344 768 WIRE 1344 1136 1184 1136 WIRE 1344 1136 1344 1072 WIRE 1424 1040 1392 1040 WIRE 1424 1040 1424 848 WIRE 1456 848 1424 848 WIRE 1552 592 1184 592 WIRE 1552 624 1552 592 WIRE 1552 848 1520 848 WIRE 1552 848 1552 704 WIRE 1552 944 1552 848 WIRE 1552 1008 1552 944 WIRE 1552 1136 1344 1136 WIRE 1552 1136 1552 1088 WIRE 1600 944 1552 944 WIRE 1664 848 1552 848 WIRE 1728 592 1552 592 WIRE 1728 800 1728 592 WIRE 1728 944 1664 944 WIRE 1728 944 1728 896 WIRE 1728 1008 1728 944 WIRE 1728 1136 1552 1136 WIRE 1728 1136 1728 1088 WIRE 1792 944 1728 944 WIRE 1840 592 1728 592 WIRE 1840 640 1840 592 WIRE 1840 768 1840 720 WIRE 1920 944 1856 944 WIRE 1920 1008 1920 944 WIRE 1920 1136 1728 1136 WIRE 1920 1136 1920 1088 FLAG 560 720 0 FLAG 1840 768 0 FLAG 688 1184 0 FLAG 1920 944 Out SYMBOL pnp 800 896 M180 SYMATTR InstName Q1 SYMATTR Value 2N5087 SYMBOL npn 1120 912 R0 SYMATTR InstName Q2 SYMATTR Value 2N3904 SYMBOL npn 1664 800 R0 SYMATTR InstName Q3 SYMATTR Value 2N3904 SYMBOL res 848 992 R0 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL res 992 800 R0 SYMATTR InstName R2 SYMATTR Value 150 SYMBOL res 672 608 R0 SYMATTR InstName R3 SYMATTR Value 100k SYMBOL res 672 992 R0 SYMATTR InstName R4 SYMATTR Value 27k SYMBOL res 1168 608 R0 SYMATTR InstName R5 SYMATTR Value 3.9k SYMBOL res 1536 608 R0 SYMATTR InstName R6 SYMATTR Value 470k SYMBOL res 1536 992 R0 SYMATTR InstName R7 SYMATTR Value 1MEG SYMBOL res 1712 992 R0 SYMATTR InstName R8 SYMATTR Value 5.6k SYMBOL res 1040 784 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName R9 SYMATTR Value 33k SYMBOL res 912 608 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName R10 SYMATTR Value 12k SYMBOL cap 736 784 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName C8 SYMATTR Value 1n SYMBOL Misc\\EuropeanPolcap 544 624 R0 SYMATTR InstName C2 SYMATTR Value 47µ SYMBOL Misc\\EuropeanPolcap 1248 784 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName C3 SYMATTR Value 10µ SYMBOL Misc\\EuropeanPolcap 1520 832 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C4 SYMATTR Value 10µ SYMBOL Misc\\EuropeanPolcap 1792 960 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName C5 SYMATTR Value 10µ SYMBOL res 1904 992 R0 SYMATTR InstName R11 SYMATTR Value 50k SYMBOL Misc\\battery 1840 624 R0 SYMATTR InstName V1 SYMATTR Value 9V SYMBOL cap 1600 960 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName C7 SYMATTR Value 1n SYMBOL Misc\\EuropeanPolcap 992 1024 R0 SYMATTR InstName C6 SYMATTR Value 100µ SYMBOL Misc\\EuropeanPolcap 528 832 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 10µ SYMBOL cap 560 1008 R0 SYMATTR InstName C9 SYMATTR Value 470p SYMBOL voltage 128 976 R0 WINDOW 39 0 0 Left 0 WINDOW 123 24 136 Left 0 SYMATTR Value2 AC 1 SYMATTR InstName V2 SYMATTR Value 0 SYMBOL res 112 864 R0 SYMATTR InstName R12 SYMATTR Value 200 SYMBOL potentiometer 1328 976 R0 WINDOW 3 -75 220 Left 0 SYMATTR Value Rtot=50K wiper=1 SYMATTR InstName P1 SYMATTR SpiceModel POT SYMBOL ind2 320 1008 R0 WINDOW 0 -43 21 Left 0 WINDOW 3 -49 70 Left 0 SYMATTR InstName L1 SYMATTR Value 1H SYMATTR SpiceLine Rser=50 SYMBOL ind2 400 1008 M0 WINDOW 0 -33 21 Left 0 WINDOW 3 -36 80 Left 0 SYMATTR InstName L2 SYMATTR Value 4H SYMATTR SpiceLine Rser=100 TEXT 2064 1576 Left 0 ;SHEET: TEXT 1888 1576 Left 0 ;SIZE: TEXT 1616 1416 Left 0 ;DESIGN TITLE: TEXT 1616 1368 Left 0 ;COMPANY: TEXT 2176 1496 Left 0 ;REV: TEXT 1616 1496 Left 0 ;AUTHOR: TEXT 2168 1576 Left 0 ;1 of 1 TEXT 1976 1576 Left 0 ;A4 TEXT 1800 1368 Left 0 ;Hotzenplotz Audio Technik GmbH TEXT 2192 1528 Left 0 ;A TEXT 1888 1496 Left 0 ;DRAWING NUMBER TEXT 1888 1528 Left 0 ;A3000-2001 TEXT 1616 1528 Left 0 ;Helmut Sennewald TEXT 1616 1576 Left 0 ;DATE: TEXT 1800 1416 Left 0 ;Mikrofon-Preamp TEXT 1800 1448 Left 0 ;SPICE model TEXT 1728 1576 Left 0 ;18.07.2004 TEXT 152 448 Left 0 !.AC DEC 100 1 100k TEXT 152 392 Left 0 ;.lib potentiometer.sub TEXT 264 1192 Left 0 !k L1 L2 0.98 TEXT 144 80 Left 0 ;Microfon preamp circuit from software magazine c't Heft 20, 2002\n----------------------------------------------------------------------------------------\nTransformer(1:2) improves SNR by 6dB.\nC7, C8, C9 filter EMI from Handy.\nC9 inreases accidentally the gain at 15kHz.\nBetter use a value of only 470pF or less for C9.\nOverall gain is about 50dB.\nUse left-mouse-click to show total noise over the whole range. TEXT 152 504 Left 0 ;.noise V(Ausgang) V2 dec 100 1 20k TEXT 1272 88 Left 0 !* This is the potentiometer\n* _____\n* 1--|_____|--2\n* |\n* 3\n*\n.SUBCKT potentiometer 1 2 3\n.param w=limit(wiper,1m,.999)\nR0 1 3 {Rtot*(1-w)}\nR1 3 2 {Rtot*(w)}\n.ENDS TEXT 160 352 Left 0 !.OP RECTANGLE Normal 0 0 2256 1600 RECTANGLE Normal 2256 1600 2048 1552 RECTANGLE Normal 2048 1600 1872 1552 RECTANGLE Normal 2256 1472 1600 1392 RECTANGLE Normal 2256 1392 1600 1344 RECTANGLE Normal 1872 1600 1600 1552 RECTANGLE Normal 2256 1552 2160 1472 RECTANGLE Normal 1872 1552 1600 1472 RECTANGLE Normal 2160 1552 1872 1472